Some Filipinos greet other persons with the phrase “good noon” especially during lunch break or lunch time which is from 12 pm to 1 pm. However, different online posts in grammar have only “good morning/afternoon/evening“ as the phrases used to greet a person during a particular time of a day. And there is no “good noon”. “Good night” is said by a person to another upon parting in the evening or when one is about to go to bed.
The phrase “good morning” is used to greet someone at the time of getting up and up to 12 pm and “good afternoon” from 12 pm up to 5 or 6 pm. Beyond that time or when it is already dark one greets another person with “good evening”.
“Good noon” as a greeting to a person at noon is used only in the Philippines, and that phrase is not used in places where English is the native language.